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[英]TPL Dataflow. Cannot attach BatchBlock to ActionBlock. Type argument cannot be inferred from usage?
[英]“bounded” BatchBlock => ActionBlock. How to complete the proper way?
我正在嘗試使用鏈接到操作塊的有界批處理塊。 我知道批處理塊中的項目進料結束時我想觸發完成鏈。
問題是:如果我的BatchBlock<T>
屬於給定的BoundedCapacity
我將不會在動作塊中觸發所有項目。
這是我的問題的一個示例,它應該(在我對TPL數據流的理解......)中打印0到124,但最終打印0到99。
必須有一些我缺少的東西...也許BoundedCapacity
意味着“當隊列數超過xxx時丟棄項目......”如果是這樣,我怎樣才能實現保證的最大內存消耗?
using System;
using System.Collections.Generic;
using System.Threading;
using System.Threading.Tasks.Dataflow;
namespace ConsoleApplication
{
class Program
{
static void Main(string[] args)
{
int itemsCount = 125;
List<int> ints = new List<int>(itemsCount);
for (int i = 0; i < itemsCount; i++)
ints.Add(i);
BatchBlock<int> batchBlock = new BatchBlock<int>(50,new GroupingDataflowBlockOptions(){BoundedCapacity = 100});
ActionBlock<int[]> actionBlock = new ActionBlock<int[]>(intsBatch =>
{
Thread.Sleep(1000);
foreach (int i in intsBatch)
Console.WriteLine(i);
});
batchBlock.LinkTo(actionBlock, new DataflowLinkOptions() { PropagateCompletion = true });
// feed the batch block
foreach (int i in ints)
batchBlock.Post(i);
// Don't know how to end the proper way... Meaning it should display 0 to 124 and not 0 to 99
batchBlock.Complete();
batchBlock.TriggerBatch();
actionBlock.Completion.Wait();
}
}
}
Post
塊上並不總是成功。 它嘗試將消息發布到塊,但如果達到BoundedCapacity
,它將失敗並返回false
。
你可以做的是使用SendAsync
而不是返回一個等待的任務。 如果塊有空間用於您的消息,則它將異步完成。 如果沒有,那么該塊返回一個任務,當它有空間接受新消息時將完成。 您可以等待該任務並限制插入:
async Task MainAsync()
{
var ints = Enumerable.Range(0, 125).ToList();
var batchBlock = new BatchBlock<int>(50, new GroupingDataflowBlockOptions { BoundedCapacity = 100 });
var actionBlock = new ActionBlock<int[]>(intsBatch =>
{
Thread.Sleep(1000);
foreach (var i in intsBatch)
Console.WriteLine(i);
});
batchBlock.LinkTo(actionBlock, new DataflowLinkOptions { PropagateCompletion = true });
foreach (var i in ints)
await batchBlock.SendAsync(i); // wait synchronously for the block to accept.
batchBlock.Complete();
await actionBlock.Completion;
}
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